Technical Abstract:
Because consumption of tomato products is correlated with protection against prostate cancer and other degenerative diseases, research on lycopene has increased. Tomato’s protective effect has been attributed to lycopene, a powerful biological antioxidant. Although tomato fruit contain primarily trans lycopene, the cis form is greater in human plasma than that in ingested foods. We wished to compare the bioavailability of trans-
and cis-lycopene isomers, using tomatoes having primarily one isomeric form or the other. To conduct this study, we obtained field-grown Tangerine and red tomatoes and had them processed into canned tomato sauce. Red tomatoes contain primarily all-trans lycopene, whereas Tangerine tomatoes contain almost all tetra-cis lycopene. Samples were analyzed for carotenoid composition at each step of processing. Twenty-four healthy men and women were fed lunches containing 31% fat and 300 mg lycopene from either Tangerine or red tomato sauce per day. Two protocols were followed with washouts before and after each study period in a randomized, crossover design: 1) a Tangerine tomato-based chili followed by a red tomato-based chili feeding and 2) red tomato-based, then a Tangerine tomato-based chili feeding. The two chilis had similar tastes, textures, and appearances. Processing red tomatoes increased the cis-isomer content, while processing tangerine tomatoes increased the number of different cis-lycopene isomers. Considerable lycopene degradation occurred, especially in Tangerine tomatoes. Consumption of the two chilies increased mean lycopene concentrations in blood. However, the percentage of lycopene in blood was much higher when Tangerine tomato-based chili was ingested. These results show that cis lycopene is more efficiently absorbed than the trans isomer, which then suggests that ingesting Tangerine tomato-based products is more effective in increasing lycopene content in blood than red tomato-based foods. Thus, fruits having different phenotypes provide a useful way to assess bioavailability of phytonutrients in human nutrition research.